The present invention relates to containers, more especially, disposable containers and to containers which can function as liners. The invention also relates to apparatus for spraying liquids (for example, spray guns) and, more especially, to the liquid containers or reservoirs of such apparatus.
There are many uses, in many different fields, for disposable containers. For example, many goods are packaged in disposable containers (e.g. bags) either before or after purchase. When the disposable container is a plastic bag, it will often be re-used by the purchaser as a disposable liner for another receptacle, for example a refuse bin. In some cases, disposable liners are produced specifically for use in other, re-usable, receptacles: in those cases, the liner may be intended to aid disposal of the contents of the receptacle (as in the case of a liner in a refuse bin); to protect the receptacle or its contents; or to facilitate, or even eliminate, the cleaning of the receptacle.
The use of a liner in a receptacle in which a substance like glue, paint or plaster is mixed or contained for use can be particularly advantageous, in terms of facilitating the cleaning of the receptacle after use and of preventing substances in the receptacle from being contaminated by the remains of other substances. Receptacles in which paints are mixed or contained for use, for example, must be clean to ensure that the colour or quality of the paint is not altered by traces of other substances: that is particularly important, as explained above, when a vehicle is being re-painted and the paint is required to match an existing one. To avoid contamination problems when mixing paints, it is often the practice in vehicle body shops to use disposable waxed paper cups as mixing containers, particularly when only a small amount of paint is required. An alternative approach, proposed in U.S. Pat. No. 4,383,635, involves the provision of a disposable container which, for use, is located in a re-usable frame-like receptacle.
In the field of spray guns, it has been proposed for various reasons that a disposable liner should be used in the reservoir of the gun (see U.S. Pat. Nos. 3,211,324, 3,255,972, 4,151,929, 4,951,875 and 5,143,294, and EP-A-0 678 334). Guns for spraying liquids (e.g. paints, garden chemicals etc.) are generally well known and typically comprise a reservoir in which a liquid to be dispensed is contained, and a spray nozzle through which the liquid is dispensed, under pressure, under the control of a trigger mechanism. The liquid may be fed from the reservoir under gravity and/or it may be entrained in a stream of pressurized fluid, for example air or water, which is supplied to the gun from an external source.
When a user wishes to change the liquid in the reservoir of a spray gun, it is usually necessary to clean the gun very thoroughly to ensure that no traces of the old liquid remain in the gun to contaminate the new liquid. That applies particularly to paint spray guns because any traces of an old batch of paint remaining in a gun may affect the colour of a new batch of paint to the extent that the new batch of paint becomes useless. This can cause problems especially in vehicle body shops where the paint applied to a vehicle is often required to match existing paint work exactly. Alternatively, if paint residues have been allowed to dry within the gun, they may flake and contaminate the new batch of paint. The cleaning of spray guns is, however, a comparatively complex and time consuming operation. Moreover, in the case of paint spray guns, the cleaning operation involves the use of comparatively large amounts of solvents which, for environmental reasons, should be handled and disposed of with care. That, in turn, can add substantially to the cost of a painting operation. It has already been suggested (see, for example, EP-A-0 678 334 mentioned above) that the use of a disposable liner in the paint reservoir (i.e. the paint pot) of a spray gun can simplify the cleaning of the gun and reduce the amount of solvent required.
The present invention is concerned with the provision of a container which is sufficiently inexpensive to be disposable and which can preferably be collapsed when it is to be disposed of but which, nevertheless, is comparatively easy to handle and to fill when in use. The invention is concerned, more especially, with the provision of such a container which is suitable for use as a liner in another receptacle. The present invention is also concerned with enabling the cleaning of spray guns and like apparatus to be simplified, and with thereby enabling the time and expense associated with that operation to be reduced.
The present invention provides a container comprising side walls and a comparatively-rigid base thermo/vacuum-formed from a plastics material; wherein the side walls are thin in comparison to the base and are collapsible, but the container is capable of standing, unsupported, on the base with the side walls extended and upright.
More especially, the present invention provides a container comprising a base, and side walls extending from the base; wherein the base and side walls are thermo/vacuum formed together from a plastics material in such a manner that the base is comparatively rigid and the side walls are thin in comparison to the base and are collapsible but the container is capable of standing unsupported, on the base with the side walls extended and upright.
A container in accordance with the invention may be used as a liner for a receptacle, the liner having a shape which corresponds to the interior of the receptacle. As a modification, the invention also provides, in combination with a receptacle, a disposable liner which fits within and has a shape corresponding to the interior of the receptacle wherein the liner is thermo/vacuum formed from a plastics material. The liner is preferably, but not necessarily, collapsible.
The present invention also provides a spray gun comprising a fluid reservoir; a removable, collapsible, liner which has a shape corresponding to, and is a close fit within, the interior of the reservoir; and a spray nozzle for dispensing fluid from within the liner; wherein the liner collapses when fluid is withdrawn from within the liner during operation of the gun.
Also in accordance with the invention, there is provided a spray gun comprising a fluid reservoir having a removable lid located in an opening in the reservoir; a removable liner located within the reservoir and secured to the reservoir, by the lid, at the periphery of the opening; and a spray nozzle for dispensing fluid from within the liner; wherein the liner is removable from the reservoir together with the lid.
The present invention also provides a gravity-fed spray gun comprising a fluid reservoir having a removable lid located in an opening in the reservoir; and a spray nozzle for dispensing fluid drawn from within the reservoir through an outlet in the lid; wherein the reservoir is removable from the gun and is capable of standing on its own to enable fluid to be loaded into the reservoir through the opening.
The invention further provides a spray gun comprising a fluid reservoir; and a spray nozzle for dispensing fluid from within the reservoir; the reservoir comprising a self-supporting container which is removable from the gun and is collapsible for disposal.
In accordance with another aspect of the invention, there is provided a fluid reservoir for attachment to a spray gun, the reservoir having a removable lid which is located in an opening in the reservoir and in which is formed a fluid outlet for the reservoir; the reservoir including a removable, collapsible, liner which has a shape corresponding to, and is a close fit within, the reservoir; wherein the liner is secured to the reservoir by the lid at the periphery of the opening and is removable from the reservoir together with the lid. The invention also provides a fluid reservoir for attachment to a spray gun, the reservoir having a removable lid which is located in an opening in the reservoir and in which is formed a fluid outlet for the reservoir, the fluid outlet being shaped for attachment to the spray gun; and a closable air vent in the end of the reservoir remote from the lid.
In accordance with yet another aspect of the invention, there is provided a liner for use in the reservoir of a spray gun, the liner being formed from a plastic material and being a close fit within the reservoir; the liner having a comparatively rigid base, and side walls which are thin in comparison to the base and are collapsible.
The present invention also provides a spray gun comprising a fluid reservoir, and a spray nozzle for dispensing fluid from within the reservoir, the reservoir having a removable lid and including a removable, generally conical, mesh filter secured in the reservoir by the lid.
The present invention also provides a gravity-feed spray gun comprising a fluid reservoir, and a spray nozzle for dispersing fluid from within the reservoir, the reservoir having a removable lid and a removable liner secured in the reservoir by the lid.
The term xe2x80x9cthermo/vacuum-formingxe2x80x9d as used herein means a process by which a sheet of material is heated to a softened condition and formed into a required shape, defined by a mould, while in that softened condition. It includes the case in which the application of a differential air pressure is used to assist in forming the material into the required shape and, in particular, includes the case in which a vacuum is produced on one side of the material to assist in forming it into the required shape (also known simply as xe2x80x9cvacuum-formingxe2x80x9d).
The term xe2x80x9ccollapsiblexe2x80x9d as used herein with reference to the side walls of a container/liner in accordance with the invention indicates that the side walls can be distorted so that, by the application of moderate pressure (e.g. hand pressure), the rim of the container can be pushed towards the base of the container, without the side walls being ruptured.
The term xe2x80x9cpaintxe2x80x9d is used herein to include all forms of paint-like coating materials that can be applied to a surface using a spray gun, whether or not they are intended to colour the surface. The term includes, for example, primers, base coats, lacquers and similar materials.